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C-reactive protein (CRP) by nephelometry

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of C-reactive protein in your blood, a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps doctors assess inflammation, track infections, or monitor conditions like autoimmune diseases."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
49455-9
Short code
VZV DNA # BAL NAA+probe
Synonyms
VZV DNA # BAL NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a CRP test to check for signs of inflammation, monitor chronic conditions (like arthritis or heart disease), or evaluate infections. It can also help guide treatment decisions, especially for conditions like rheumatoid arthritis or heart attacks.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Higher-than-normal CRP levels often indicate inflammation, infections, or other health issues. However, results alone don’t diagnose a condition—they’re used alongside other tests and symptoms.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, lupus, or heart disease. It may also help detect infections (e.g., pneumonia) or assess response to treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP levels can rise acutely with infections, chronic inflammation, or autoimmune diseases. While it’s not specific to any single condition, it’s a useful marker for overall inflammation in the body.

Short name

CRP (Nephelometry)

Frequently asked questions

What causes CRP levels to change?
CRP levels can increase due to infections (like flu or urinary tract infections), injuries, or chronic conditions like arthritis. Stress, smoking, or certain medications may also affect CRP levels.
How often should I get this test?
Your provider will determine how often you need this test based on your health needs. Some people get it every few months to monitor chronic conditions, while others may need it only if symptoms appear.
Can diet or lifestyle affect CRP levels?
Yes! Eating a heart-healthy diet, staying active, and managing stress can help lower CRP levels. Avoiding smoking and controlling weight may also improve inflammation markers.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy